Electrical pulse producing apparatus



Dec. 1, 1964 R'. ALLEN 3,159,732

ELECTRICAL PULSE PRODUCING APPARATUS Filed 0013. 12, 1962 INVENTOR ROBERT ALLEN ATTORNEYS.

United States Patent Filed Oct. 12, 1962, Ser. No. 230,106 13 Claims. (Cl. 200-153) This invention relates to apparatus for producing isolated trains of whole electrical pulses.

Dial pulsing standards for calibrating dial test sets employed in the manufacture of telephones is one example of the use of isolated trains of electrical pulses. These pulse trains to be suitable for this use must consist only of whole pulses, that is, each train must begin and end with pulses of the same duration as each of the remaining pulses in the train. Also, the trains must have accurately controlled speed and percent break characteristics, the former being the number of pulses per second and the latter being the ratio of the time interval between two successive pulses to the duration of one pulse.

A prior device for producing such pulse trains included a circular slip ring comprising a plurality of conducting segments electrically isolated from each other at the surface of the slip ring by non-conducting segments but electrically connected to a single terminal. An electrical brush, drivably connected through a slip clutch to a synchronous motor, was adapted to rotate around and in contact with the surface of the slip ring, the brush having a stationary or rest position in which it was in contact with a non-conducting segment. The device was connected between a source of continuous electric current and a dial test set and when calibration of the latter was required the brush was rotated one revolution around the slip ring, beginning and ending its rotation at its said rest position. As the brush was rotated, the electric current was transmitted to the test set as an electric pulse each time the brush contacted a conducting segment. 'The resulting pulse train consisted of as many pulses as conducting segments in the slip ring while the speed and percent break characteristics of the train were determined by the brush speed and the ratio of the length of a non-conducting segment to that of a conducting segment, respectively. Also, the pulse train consisted only of whole pulses by reason of the fact that the brushbegan its rotation in contact with a non-conducting segment.

In use of such a device, however, constant vigilance and frequent maintenance were necessary to ensure that the desired speed and percent break characteristics did not vary as a result of wear of the brush and slip ring or of damage to the slip ring surface or of metal worn from the conducting segments becoming imbedded in the nonconducting segments, etc.

It is a primary object of the present invention to provide apparatus which does not require such constant vigilance and frequent maintenance and yet is simple, rugged and dependable in operation.

Basically, the present invention provides apparatus for selecting trains of pulses from a continuous supply of pulses, as opposed to hitherto known apparatus which actually produced the trains of pulses as desired. The difiiculty arises, inputting the present invention into practice, in arranging that the selected trains always start and end with complete pulses and it may be that for this reason prior inventors have not been able to utilize selection rather than production of pulse trains. On the other 3,159,732 Patented Dec. 1, 1964 The apparatus of my invention comprises an interrupting means normally preventing transmission of a continuous supply of pulses, a control means operatively connected to said interrupting means so that when the control means is operated the interrupting means is rendered inoperative thereby permitting transmission of the pulses, and a selecting means to be driven constantly at a rate proportional to the rate of supply of pulses and which has arranged thereon an engaging means and a release means for the control means.

The control means is operated only when moved into the path of and engaged by the engaging means and is normally held out of said path. Moreover, the engaging means and the release means are spacially arranged on the selecting means at locations and at a distance apart, depending on the rate of supply of pulses and the speed at which the selecting means is to be driven, such that the control means can only be engaged and released between complete pulses and is retained in the meantime by the selecting means for the time required for transmission of the selected train.

Actuating means may be provided for moving the control means into the path of theengaging means when desired. This actuating means may be manually operated and is normally adapted to move the control means to transmit one train of pulses only each time it is operated. However, means may be provided for locking the actuating means in a position wherein the control means is repeatedly acted upon thereby, so that repeated pulse trains are transmitted, succeeding pulse trains being separated by equal time intervals.

An embodiment of the invention is described below by way of example, with reference to the accompanying drawing, which is a diagrammatic representation of a pulsing apparatus incorporating all of the above features.

The apparatus shown comprises in general: a pulsing means 10 for producing a continuous supply of pulses; an interrupting means 11 normally preventing transmission of the pulses; a control means or arm 12 which, when operated, renders the interrupting means 11 inoperative to permit transmission of the pulses; a selecting means 13 for operating the' control means 12, when the latter has been suitably conditioned, for a time interval during which a desired number of whole pulses is transmitted; an actuating means 14 manually operable to a position from which it is further operable automatically to condition the control means 12 such further operation being controlled by a trip means 15, a retaining means 16 and a guide means 17; and a drive means 18 for driving the pulsing, selecting and trip means in predetermined re lation to one another.

The pulsing means 10 consists of a pair of electrical contacts 19 and 2t) electrically connectable to a dial test set by means of wires 21 and 22. Contact 19 is mounted on a movable arm 23 which is biased away from contact Zii. A cam 24, mounted on a rotatable shaft 25 having a gear 26 is adapted when rotated to act on the arm 23 to close contacts 19 and 20 once every revolution.

The interrupting means 11 comprises a quick acting switch in the form of apair of normally closed electrical contacts (not shown) connected to the wires Hand 22 in parallel with contacts 19 and 20. One of these normally closed contacts is mounted on the arm 12. The arm 12 is mounted on the interrupting means 11 at one end so that it normally occupies the inoperative position shown in the drawing, in which the contacts are closed,

' but can be moved downwards to open the contacts. It

' The selecting means 13 comprises a disk 28 mounted I for rotation in the direction of the arrow on a rotatable shaft 29 having a gear 30'. The disk has first and second radial slots 31 and 32, respectively, which are open at the periphery of the disk. n the trailing edge of the first slot 31 is a lip 33 extending in the direction of rotation and upwardly from the upper surface of disk 28. A similar lip 34 extends from the leading edge of the second slot 32 in a counter-rotational direction. Disk 28 is located with respect to the interrupting means 11 so that the the free end 27 of arm 12 in the inoperative position shown, overlies and is spaced from the upper surface of the disk and from the lips 33 and 34. The arm 12 extends radially toward the center of disk 28 but not beyond the inner ends of the radial slots 31 and 32.

The actuating means 14 consists of an axially-bored cylinder 35 which is split transversely, as shown at 36, at an angle to its longitudinal axis into first and second cylindrical components 37 and 38, respectively. A rod 39 passes through axial bore in the cylinder and extends beyond both ends thereof. The first component 37 is rotatably mounted on the rod 39 and the second component 38 is both rotatable and slidable thereon. A push button 40 is rigidly attached to the end of the rod that extends from the first component 37 while the other end of the rod is slidably and rotatably received in a supporting structure shown fragmentarily at 41 to support the cylinder 35 substantially parallel to the shaft 29. A compression spring 42 surrounds the rod 39 between the free end 61 of the second component 38 and the supporting structure 41. The actuating means 14 is arranged so that, when it is operated, as will be described hereinafter, the free end 61 of the second component 38 acts on the arm 12.

The trip means 15 is a cam-like disk 43 mounted on shaft 29 and having a single tooth 44 extending radially and downwardly from its periphery. The disk 43 is disposed in a plane lying beneath and spaced from a radial projection 45 on the second component 38 when the actuating means 14 is inoperative as shown.

The retaining means 16 is a shaped spring member 46 having bent portions extending in opposite directions at either end and providing a foot 47, by which the member 46 is resiliently mounted, and a lip 48 which is biased toward the cylinder 35. The lip 48 is prevented from contacting the cylinder 35 by an adjustable follower or bolt 49 threaded through the spring member 46 and contacting.

the cylindrical surface of the second component 38. A depression 50 in this cylindrical surface is arranged to co-act with the bolt 49 as will be described later.

The guide means 17 consists of a rigidly mounted member 51 having a slot 52 extending parallel to the axis of the cylinder 35 and adapted to embrace a pair of radial projections 53 and 54 on the rod 39 and the first component 37, respectively. The slot is provided with a detent 55 which, as will be described later, is adapted to receive the radial projection 53.

The driving means 18 includes a synchronous motor (not shown) drivingly connected to the shaft 56 having drive gear 57 mounted thereon. A pair of intermediate gears 58 and 59 are secured together and are coaxially mounted for rotation on a stub shaft 60. Drive gear 57 meshes with intermediate gear 58 which, in turn, meshes with the gear 26 of the pulsing means 10. Intermediate gear 59 meshes with gear 30 of the selecting means 13 and the trip means 15. The ratios of the two gear trains and the counter-rotational displacement of the second slot 32 from the first slot 31 in disk 28 are selected so that during a successive rotation of the first and second slots past the location of arm 12 the number of revolutions of cam 24 equals the number of pulses required in the pulse train. In addition, disk 28 is angularly located on shaft 29 so that when either of the slots coincides with arm 12 the contacts 19 and 20 of the pulsing means are open. The disks 43 and 28 are angularly located relative to one another so that the tooth 44 of disk 43 leads the first slot 31 of disk 28 by a small angular distance to be fully described in the following operational description of this embodiment of the invention.

Whenever the synchronous motor is running, contacts 19 and 20 open and close once for every revolution of cam 24. An electric current supplied to these contacts from the dial test set over either of wires 21 or 22 would be returned to the test set over the other wire as a stream of electrical pulses having a speed determined by the rotational speed of cam 24, except that, when the apparatus is inoperative as shown in the drawing, the normally closed contacts of the interrupting means 11 are operative to short circuit the electric current back to the test set and prevent it from passing through contacts 19 and 20. Therefore, even though contacts 19 and 20 may be operated continuously, no pulses are transmitted to the test set so long as the interrupting means 11 is operative.

Calibration of the test set is achieved by manually depressing the push-button 40 to move the cylinder 35 and the rod 39 axially downward, against the action of the spring 42, from inoperative position to an intermediate position in which the upper end of the first component 37 is just below the lip 48 of spring member 46. In this position, the depression 50 in second component 38 coincides with the bolt 49, which is urged under the biasing action of the spring member 46 to the bottom of the depression thereby permitting the member 46 to move toward the cylinder 35 until the lip 48 overlies the upper end of the first component 37 to prevent the return of cylinder 35 to the inoperative position by the compressed spring 42. In addition, the arm 12 is engaged by the free end 61 of second component 38 and is thereby moved downwardly until its free end 27 is in a plane that just overlies the lips 33 and 34 of disk 28, but is not moved down far enough to open the contacts of the interrupting means 11.

The radial projection 45 on second component 38 now lies in the plane of the rotating disk 43 and is subsequently engaged by the tooth 44 which acts thereon to rotate the second component 38 about is longitudinal axis. This rotation results in a downward axial displacement of the second component with respect to the first component 37 by interaction between their diagonal mating surfaces at 36 because the first component 37 is held against rotation by engagement of the radial projection 54 in the slot 52 of guide means 17. The second component 38 thus moves the arm 12 further toward the upper surface of the disk 28 until the free end 27 of the arm lies below the upper edge of the lip 33 where it is engaged by the latter. The tooth 44 of disk 43 and the first slot 31 of disk 28 are angularly related so that the free end 27 is engaged by the lip 33 almost immediately upon its reaching this position. Immediately after engagement of the free end 27, the tooth 44 becomes disengaged from the radial projection 45 at which point the second cylindrical component 38 has been rotated sufficiently so that the depression 50 no longer coincides with the bolt 49 which then is in contact once again with the cylindrical surface of the second component. The movement of the bolt 49 out of the depression 50 urges the spring member 46 away from the cylinder 35 thereby disengaging the lip 48 from the free end of first component 37. The compression spring 42, acting upon the free end 43 of second component 38, returns the cylinder 35 and the rod 39 to the normal inoperative position shown in the drawing.

Upon engagement with the free end 27 of arm 12, the lip 33 forces the free end downwardly through the slot 31 to the undersurface of the disk 28, in which position, the arm 12 opens the contacts of interrupting means 11, whereby an electric current from the test set is allowed to pass through the successively opening and closing contacts 19 and 20 and return to the test set as a stream of electrical pulses. The arm 12 is retained in this operative position by engagement of the free end 27 with the undersurface of disk 28 until the second slot 32 coincides with the arm whereupon the free end 27, due to the upward bias on the arm, returns through the slot 32 to allow the arm to return to its upper inoperative position. The lip 34 on the second slot 32 acts as a damping device to control the return speed of the biased arm 12 therethrough. The interrupting means thus becomes operative again and the stream of pulses to the test set is terminated. Because the contacts 19 and 20 are open when the slots 31 and 32 coincide with the arm 12 the train of pulses begins and ends with a whole pulse ensuring that only whole pulses are transmitted.

If several successive trains of pulses are desired, the push button 40 is depressed as described above and then rotated to engage the radial projection 53 in the deten t 55 of guide means 17. The actuating means 14 is thereby retained in the intermediate position regardless of the action of the retaining means 16. The second component 38 is successively moved from this intermediate position to the operative position and returned by the trip means 15 and the compression spring 42. The result is that the arm 12, after being rendered operative by the selecting means 13 and after being returned to the inoperative position as described above, is automatically re-conditioned for re-engagement by the lip 33. This action is repeated so long as the projection53 is engaged in the detent 55 and it results in successive trains of pulses being transmitted to the dial test set in cyclical manner.

What I claim as my invention is:

1. An apparatus for producing isolated trains of whole electrical pulses from a continuous supply of pulses comprising interrupting means normally operative to prevent transmission of the pulses, control means having a normal inoperative position and an operative position, the interrupting means being connected with the control means such that it is inoperative when the control means is in the operative position, selecting means movable constantly at a rate proportional to the rate of supply of pulses, engaging means on the selecting means for engaging the control means when the latter is suitably conditioned and move the control means to the operative position, and releasing means on the selecting means for releasing the control means from the selecting means, the engaging and releasing means being in predetermined positions on the selecting means such that the control means is engaged between two successive pulses and, after a predetermined number of whole pulses are transmitted during engagement of the control means by the selecting means, the control means is released between two successive pulses.

2. An apparatus as claimed in claim 1 wherein the selecting means comprises a disk rotatable at a speed proportional to the rate of supply of pulses, the control means comprise a movable arm having a free end portion overlying and spaced from one surface of the disk when said arm is in the inoperative position, and the engaging and releasing means comprise first and second radial slots respectively in the disk, said slots extending to the periphery of the disk and being angularly spaced apart such that said predetermined number of whole pulses are supplied during the time interval for rotation of said first and second slots in that order past said arm, said first slot having a lip on its trailing edge, said lip extending outwardly from said one surface and in the direction of rotation of the disk, said free end portion of the arm being moved toward said one surface when said arm is suitably conditioned whereby said free end portion is engaged by said lip and urged through said first slot to the other surface of the disk in which position said arm is in the operative position, said second slot permitting said free end portion to return to its spaced position overlying said'one'surface after said time interval. I

3. An apparatus as claimed in claim 1 further comprising actuating means'operable at will to condition the control means for engagement by the engaging means.

4. An apparatus as claimed in claim 3 further comprising trip means movable with the selecting means and operable on the actuating means when the latter is moved at will from an inoperative position to an intermediate position to move a part thereof further to an operative position in which it conditions the control means, and retaining means for engaging said retaining the remainder of the actuating means in the intermediate position until said part is in the operative position and the control means is engaged by the engaging means.

5. An apparatus as claimed in claim 4 wherein the actuating means comprises an elongated cylindrical body movable at will in the direction of its longitudinal axis from an inoperative position to an intermediate position, and biasing means urging said body to the inoperative position, said body being split transversely at an angle to its longitudinal axis into first and second components, said components thereby having diagonal mating endsurfaces, the second component being rotatable about the longitudinal axis and the first component being non-rotatable, the retaining means is engaging the first component in the intermediate position and thereby preventing return of said components to the inoperative position, and the trip means comprising cam means rotatable in synchronism with the movement of the selecting means, a radial projection being provided on the second component, the cam means being engageable with said projection when said components are in the intermediate position and to rotate the second component through a predetermined angular distance with respect to the first component, such rotation causing interaction of said diagonal surfaces and a resulting axial movement of the second component to the operative position, the second component being adapted when so moved to condition the control means, the engaging means being engageable with the control means at the instant the latter is conditioned, the cam means being disengageable from said projection when the second component has been rotated through said predetermined angular distance, the retaining means being disengageable from the first component when the second component has beenso rotated to permit the biasing means to return said components to the inoperative position.

6. An apparatus as claimed in claim 5 wherein an abutment is provided on the first component, the retaining means comprising a resilientlymounted catch biased toward said body and engaging the abutment on the first component when said body is in the intermediate position to retain the first component in the intermediate position, and a follower connected with said catch to slidably contact the cylindrical surface of said body and normally urge said catch away from said body, and a depression is provided in the cylindrical surface of the second component and so located therein to coincide with the follower when the second component is in the intermediate position, the follower being movable to the bottom of said depression when coincident therewith to permit said catch to engage said abutment, said depression being so arranged to move away fromthe follower when the second component moves to the operative position whereby the follower is returned to normal contact with the cylindrical surface of the body to urge said catch out of engagement with said abutment and thereby permit the biasing means to return said components to the inoperative position.

7. An apparatus as claimed in claim 6 wherein the actuating means further comprises a push button mounted on the first component for manual operation of said body to the intermediate position.

8. An apparatus as claimed in claim 7 wherein the pushbutton is rotatable about its central axis with respect to the first component, said apparatus further comprising guide means cooperable with the push button to prevent rotation thereof from a normal angular position except 7 when said body is in the intermediate position, and locktion until the push button is manually returned to its normal angular position, the second component thereby being retained for successive movement between its intermediate and operative position by the trip means and biasing means to repeatedly condition the control means for successive operation thereof by the engaging and releasing means on the selecting means whereby isolated trains of said predetermined numbers of whole pulses are transmitted in a cyclical manner.

9. An apparatus as claimed in claim 8 wherein a radial projection is provided on the push button, the guide means comprising a member having a longitudinal slot therein embracing said projection to ensure only reciprocal motion of the push button between the inoperative and intermediate positions of said body, and the locking means comprising a detent in one side of said slot for receiving and engaging said projection upon rotation of the push button when said body is in the intermediate position.

10. An apparatus as claimed in claim 1 further comprising pulsing means for producing said continuous supply of pulses.

11. An apparatus as claimed in claim 10 wherein the pulsing means comprises a pair of electrical contacts, a

8 cam rotatable to successively open and close said pair of contacts, and driving means for rotating said cam whereby said continuous supply of pulses is produced from an electric current supplied to said pair of contacts.

12. An apparatus as claimed in claim 11 wherein the driving means is further adapted to move the selecting means only when the cam is driven and at a rate proportional to the rate at which the cam is driven.

13. An apparatus as claimed in claim 1 wherein the interrupting means comprises a pair of electrical contacts having a normally closed position to short circuit the supply of pulses, and the control means comprises an arm connected with one contact of said pair of contacts and movable to the operative position by the selecting means to move said one contact away from the other contact thereby opening said pair of contacts to permit transmission of the pulses.

No references cited.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

1. AN APPARATUS FOR PRODUCING ISOLATED TRAINS OF WHOLE ELECTRICAL PULSES FROM A CONTINUOUS SUPPLY OF PULSES COMPRISING INTERRUPTING MEANS NORMALLY OPERATIVE TO PREVENT TRANSMISSION OF THE PULSES, CONTROL MEANS HAVING A NORMAL INOPERATIVE POSITION AND AN OPERATIVE POSITION, THE INTERRUPTING MEANS BEING CONNECTED WITH THE CONTROL MEANS SUCH THAT IT IS INOPERATIVE WHEN THE CONTROL MEANS IS IN THE OPERATIVE POSITION, SELECTING MEANS MOVABLE CONSTANTLY AT A RATE PROPORTIONAL TO THE RATE OF SUPPLY OF PULSES, ENGAGING MEANS ON THE SELECTING MEANS FOR ENGAGING THE CONTROL MEANS WHEN THE LATTER IS SUITABLY CONDITIONED AND MOVE THE CONTROL MEANS TO THE OPERATIVE POSITION, AND RELEASING MEANS ON THE SELECTING MEANS FOR RELEASING THE CONTROL MEANS FROM THE SELECTING MEANS, THE ENGAGING AND RELEASING MEANS BEING IN PREDETERMINED POSITIONS ON THE SELECTING MEANS SUCH THAT THE CONTROL MEANS IS ENGAGED BETWEEN TWO SUCCESSIVE PULSES AND, AFTER A PREDETERMINED NUMBER OF WHOLE PULSES ARE TRANSMITTED DURING ENGAGEMENT OF THE CONTROL MEANS BY THE SELECTING MEANS, THE CONTROL MEANS IS RELEASED BETWEEN TWO SUCCESSIVE PULSES. 